Amazon's Kindle Fire has sold out, the e-retail giant announced Thursday, as speculation swirls over a secretive Santa Monica press conference scheduled for Sept. 6.

The Fire entered the tablet market — of which it now claims 22 percent — nine months ago.

"We're grateful to the millions of customers who have made Kindle Fire the most successful product launch in the history of Amazon," CEO and founder Jeff Bezos said in a statement. "Kindle Fire is sold out, but we have an exciting roadmap ahead — we will continue to offer our customers the best hardware, the best prices, the best customer service, the best cross-platform interoperability and the best content ecosystem."